Nowadays, electronic cigarettes are widely used to replace the conventional tobacco cigarettes. FIG. 1A is a schematic cross-sectional view illustrating a conventional electronic cigarette. FIG. 1B is a schematic cross-sectional view illustrating the structure of the atomizer of the conventional electronic cigarette. As shown in FIGS. 1A and 1B, the electronic cigarette comprises a first casing 1a, a second casing 1b, a power supply device 2, a sensing unit 3, an atomizer 4 and a liquid storage structure 5. The first casing 1a and the second casing 1b are thin-wall metal pipes, e.g., stainless steel pipes. The power supply device 2, the sensing unit 3, the atomizer 4 and the liquid storage structure 5 are disposed within the first casing 1a and the second casing 1b. After the first casing 1a and the second casing 1b are combined together, the electronic cigarette is assembled. The length and diameter of the electronic cigarette are similar to those of the conventional tobacco cigarette. The power supply device 2 and the sensing unit 3 are disposed within the first casing 1a. The first casing 1a comprises at least one inlet 1c, which is disposed near the sensing unit 3. The atomizer 4 and the liquid storage structure 5 are disposed within the second casing 1b. The atomizer 4 is fixed and supported on a bracket 7. The atomizer 4 comprises an electric heater 41, a liquid infiltration part 42 and a liquid transfer part 43. The liquid infiltration part 42 is disposed around the electric heater 41. The liquid transfer part 43 tightly holds the liquid infiltration part 42. The electric heater 41 has a hollow structure. The liquid storage structure 5 is disposed within the second casing 1b. The liquid storage structure 5 comprises a passageway 51 and a liquid container 52. The passageway 51 is formed within the liquid storage structure 5 for allowing the gas to pass through. The liquid container 52 is disposed around the passageway 51. A communication part 431 of the liquid transfer part 43 of the atomizer 4 is contacted with the liquid container 52. Consequently, the cigarette liquid in the liquid container 52 can be absorbed by the liquid infiltration part 42 through the communication part 431 of the liquid transfer part 43. Moreover, an intake-and-electric-connection element 10 is disposed between the atomizer 4 and the sensing unit 3. An airflow path is defined by the intake-and-electric-connection element 10. Moreover, the intake-and-electric-connection element 10 is in communication with the passageway 51 of the liquid storage structure 5. After the ambient airflow is fed into the at least one inlet 1c, the airflow is transferred to the passageway 51 of the liquid storage structure 5 through the sensing unit 3 and the electric heater 41. The electronic cigarette further comprises an electrode ring 8. The electrode ring 8 is electrically connected with two pins of the electric heater 41. Moreover, the electrode ring 8 is electrically connected with the power supply device 2 through the electric connection between the intake-and-electric-connection element 10 and the sensing unit 3. The electric circuit of the electronic cigarette is selectively enabled or disabled according to the result of sensing the airflow by the sensing unit 3. In one embodiment, the sensing unit 3 can switch on or off the electric circuit of the power supply device 2 according to the airflow detected by the sensing unit 3. Moreover, a mouthpiece 9 is disposed on an end of the second casing 1b and in communication with the passageway 51 of the liquid storage structure 5.
The operations of the electronic cigarette will be described as follows. As mentioned above, the cigarette liquid in the liquid container 52 can be absorbed by the liquid infiltration part 42 through the communication part 431 of the liquid transfer part 43. When the user smokes and inhales the air through the mouthpiece 9, the airflow flows through the electronic cigarette. According to the sensing result of the sensing unit 3, the electric circuit of the electronic cigarette is enabled. After the electric circuit of the electronic cigarette is enabled, the power supply device 2 provides electric power to the electrode ring 8. Consequently, the electric heater 41 is enabled to heat the cigarette liquid. Meanwhile, the cigarette liquid in the liquid infiltration part 42 is heated and atomized by the electric heater 41. Consequently, the user inhales the atomized vapor from the passageway 51 of the liquid storage structure 5 through the mouthpiece 9. When the user stops smoking, the airflow does not flow through the electronic cigarette. According to the sensing result of the sensing unit 3, the electric circuit of the electronic cigarette is disabled. Meanwhile, the electric heater 41 stops heating the cigarette liquid.
As mentioned above, the cigarette liquid is transferred to the liquid infiltration part 42 through the communication part 431 of the liquid transfer part 43. However, this design has some drawbacks.
Firstly, it is difficult to precisely control the amount of the cigarette liquid to be transferred to the liquid infiltration part 42 through the communication part 431 of the liquid transfer part 43. Consequently, the cigarette liquid is not uniformly absorbed by the liquid infiltration part 42. In case that a site of the liquid infiltration part 42 absorbs a small amount of the cigarette liquid, the liquid drop is not uniformly generated. After the liquid drop of the cigarette liquid is heated by the electric heater 41, the atomized vapor has a burning taste that is unpleasing to the user.
Secondly, since the amount of the cigarette liquid to be transferred to the liquid infiltration part 42 cannot be precisely controlled, another problem occurs. Especially when the mouthpiece 9 faces up, the force of gravity continuously transfers the cigarette liquid from the liquid container 52 to the liquid infiltration part 42. Once the cigarette liquid absorbed by the liquid infiltration part 42 reaches a saturation state, the cigarette liquid drops down to the bracket 7 and the intake-and-electric-connection element 10. Then, the cigarette liquid drops down through the sensing unit 3 and leaks out from the at least one inlet 1c. Meanwhile, a liquid leakage problem occurs.
Moreover, there are some differences between the electronic cigarettes and the real cigarettes. For example, when people smoke the real cigarettes, they are accustomed to smoking quickly, shortly and laboriously. Whereas, people smoke the electronic cigarettes lengthily and gently. While the user smokes the real cigarette and inhales a great amount of oxygen gas, the user can quickly get the wanted amount of smoke because the tobacco is burnt and atomized faster. However, while the user smokes the conventional electronic cigarette, the electric power to be transmitted to the electric heater and the heating speed cannot be adjusted. If the heating speed is too fast, the cigarette liquid is atomized by the atomizer very quickly. Since the cigarette liquid of the conventional electronic cigarette is provided according to a siphon effect, the speed of providing the cigarette liquid is too slow. Under this circumstance, the amount of the atomized vapor is insufficient or the atomized is burnt out. Since the electric power transmitted to the atomizer of the conventional electronic cigarette is fixed, the user has to smoke the electronic cigarette lengthily and gently to provide a sufficient heating time to the atomizer. That is, the conventional method of atomizing the cigarette liquid of the electronic cigarette still has some drawbacks. The above problems lead to significant differences between the real cigarette and the electronic cigarette. Because of these drawbacks, the user does not prefer to choose the electronic cigarette in replace of the real cigarette.
For solving the drawbacks of the conventional technologies, the present invention provides an improved electronic cigarette.